Re: HP-17B Language selection disappeared. Message #9 Posted by Christoph Giesselink on 13 Feb 2012, 1:34 p.m., in response to message #5 by Don Shepherd
Quote:
You could perform the self-test. If you get OK-17B-I, I believe that means you have the international version, which has the language selections. If you get OK-17B-E, you have the English-only version.
I've never heard of an international version turning into an English-only version before. If true, that would seem to be a ROM defect.
I fully agree with Don.
The difference between the International and the English version of the 17B is the additional 32KB ROM chip mapped at address #20000. The English/Basic 64KB ROM (inside the Lewis CPU chip) look at startup at address #20000 for the sequence 20000:F3C5A (output of the build in memory scanner). If the sequence is found the English ROM calls a specified address inside the additional 32KB ROM for the international initialization.
Here're HP82240B log's of the self test (done with Emu42 and HP82240B printer simulation)
17B International:
SPD 1004240
ROM OK
ROM2 OK
DRAM OK
URAM OK
OK-17B-I
COPYRIGHT HP 1987
17B English:
SPD 1005392
ROM OK
DRAM OK
URAM OK
OK-17B-E
COPYRIGHT HP 1987
One difference between the International and English version is the already mentioned OK message. The 2nd difference is the additional "ROM2 OK" message at the International version.
Any repeating byte sequence at address #20000 like 20000:A3A3A3 looks like an open data bus, in the case of the International version that means a defect around the additional ROM chip.
Christoph
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